52 Pa. Code § 69.13
(a) The SOLR is the NGDC or an NGS, which has been designated by the Commission under section 2207 of the act (relating to obligations to serve) to provide SOLR service. Each of the following services will be provided by an SOLR:
(c) An SOLR under subsection (a)(3) should provide sufficient supplies as to quantity, quality, pressure and location to meet the operational reliability requirements of the NGDC’s system including a failure of one or more NGSs to do one of the following:
This section cited in 52 Pa. Code § 69.11 (relating to definitions); and 52 Pa. Code § 69.19 (relating to operational and capacity councils).